tui

Features

• Update crossterm to 0.20.
• Add From<Cow<str>> implementation for text::Text (#471).
• Add option to right or center align the title of a widgets::Block (#462).

Fixes

• Apply label style in widgets::Gauge and avoid panics because of overflows with long labels (#494).
• Avoid panics because of overflows with long axis labels in widgets::Chart (#512).
• Fix computation of column widths in widgets::Table (#514).
• Fix panics because of invalid offset when input changes between two frames in widgets::List and
  widgets::Chart (#516).

Features

• Update crossterm to 0.19.
• Update rand to 0.8.
• Add a read-only view of the terminal state after the draw call (#440).

Fixes

• Remove compile warning in TestBackend::assert_buffer (#466).

Breaking changes

New API for the Table widget

The Table widget got a lot of improvements that should make it easier to work with:

• It should not longer panic when rendered on small areas.
• Rows are now a collection of Cells, themselves wrapping a Text. This means you can style
  the entire Table, an entire Row, an entire Cell and rely on the styling capabilities of
  Text to get full control over the look of your Table.
• Rows can have multiple lines.
• The header is now optional and is just another Row always visible at the top.
• Rows can have a bottom margin.
• The header alignment is no longer off when an item is selected.

Taking the example of the code in examples/demo/ui.rs, this is what you may have to change:

     let failure_style = Style::default()
         .fg(Color::Red)
         .add_modifier(Modifier::RAPID_BLINK | Modifier::CROSSED_OUT);
-    let header = ["Server", "Location", "Status"];
     let rows = app.servers.iter().map(|s| {
         let style = if s.status == "Up" {
             up_style
         } else {
             failure_style
         };
-        Row::StyledData(vec![s.name, s.location, s.status].into_iter(), style)
+        Row::new(vec![s.name, s.location, s.status]).style(style)
     });
-    let table = Table::new(header.iter(), rows)
+    let table = Table::new(rows)
+        .header(
+            Row::new(vec!["Server", "Location", "Status"])
+                .style(Style::default().fg(Color::Yellow))
+                .bottom_margin(1),
+        )
         .block(Block::default().title("Servers").borders(Borders::ALL))
-        .header_style(Style::default().fg(Color::Yellow))
         .widths(&[
             Constraint::Length(15),
             Constraint::Length(15),

Here, we had to:

• Change the way we construct Row which is no
  longer an enum but a struct. It accepts anything that can be converted to an iterator of things
  that can be converted to a Cell
• The header is no longer a required parameter so we use
  Table::header to set it.
  Table::header_style has been removed since the style can be directly set using
  Row::style. In addition, we want
  to preserve the old margin between the header and the rest of the rows so we add a bottom margin to
  the header using
  Row::bottom_margin.

You may want to look at the documentation of the different types to get a better understanding:

• Table
• Row
• Cell

Fixes

• Fix handling of Non Breaking Space (NBSP) in wrapped text in Paragraph widget.

Features

• Add Style::reset to create a Style resetting all styling properties when applied.
• Add an option to render the Gauge widget with unicode blocks.
• Manage common project tasks with cargo-make rather than make for easier on-boarding.

Features

• Add LineGauge widget which is a more compact variant of the existing Gauge.
• Bump crossterm to 0.18

Fixes

• Take into account the borders of the Table widget when the widths of columns is controlled by
  Percentage and Ratio constraints.

Features

• Make it easier to work with string with multiple lines in Text (#361).

Fixes

• Fix a style leak in Graph so components drawn on top of the plotted data (i.e legend and axis
  titles) are not affected by the style of the Datasets (#388).
• Make sure BarChart shows bars with the max height only when the plotted data is actually equal
  to the max (#383).

Features

• Add the dot character as a new type of canvas marker (#350).
• Support more style modifiers on Windows (#368).

Fixes

• Clearing the terminal through Terminal::clear will cause the whole UI to be redrawn (#380).
• Fix incorrect output when the first diff to draw is on the second cell of the terminal (#347).

Breaking changes

Easier cursor management

A new method has been added to Frame called set_cursor. It lets you specify where the cursor
should be placed after the draw call. Furthermore like any other widgets, if you do not set a cursor
position during a draw call, the cursor is automatically hidden.

For example:

fn draw_input(f: &mut Frame, app: &App) {
  if app.editing {
    let input_width = app.input.width() as u16;
    // The cursor will be placed just after the last character of the input
    f.set_cursor((input_width + 1, 0));
  } else {
    // We are no longer editing, the cursor does not have to be shown, set_cursor is not called and
    // thus automatically hidden.
  }
}

In order to make this possible, the draw closure takes in input &mut Frame instead of mut Frame.

Advanced text styling

It has been reported several times that the text styling capabilities were somewhat limited in many
places of the crate. To solve the issue, this release includes a new set of text primitives that are
now used by a majority of widgets to provide flexible text styling.

Text is replaced by the following types:

• Span: a string with a unique style.
• Spans: a string with multiple styles.
• Text: a multi-lines string with multiple styles.

However, you do not always need this complexity so the crate provides From implementations to
let you use simple strings as a default and switch to the previous primitives when you need
additional styling capabilities.

For example, the title of a Block can be set in the following ways:

// A title with no styling
Block::default().title("My title");
// A yellow title
Block::default().title(Span::styled("My title", Style::default().fg(Color::Yellow)));
// A title where "My" is bold and "title" is a simple string
Block::default().title(vec![
    Span::styled("My", Style::default().add_modifier(Modifier::BOLD)),
    Span::from("title")
]);

• Buffer::set_spans and Buffer::set_span were added.
• Paragraph::new expects an input that can be converted to a Text.
• Block::title_style is deprecated.
• Block::title expects a Spans.
• Tabs expects a list of Spans.
• Gauge custom label is now a Span.
• Axis title and labels are Spans (as a consequence Chart no longer has generic bounds).

Incremental styling

Previously Style was used to represent an exhaustive set of style rules to be applied to an UI
element. It implied that whenever you wanted to change even only one property you had to provide the
complete style. For example, if you had a Block where you wanted to have a green background and
a title in bold, you had to do the following:

let style = Style::default().bg(Color::Green);
Block::default()
  .style(style)
  .title("My title")
  // Here we reused the style otherwise the background color would have been reset
  .title_style(style.modifier(Modifier::BOLD));

In this new release, you may now write this as:

Block::default()
    .style(Style::default().bg(Color::Green))
    // The style is not overidden anymore, we simply add new style rule for the title.
    .title(Span::styled("My title", Style::default().add_modifier(Modifier::BOLD)))

In addition, the crate now provides a method patch to combine two styles into a new set of style
rules:

let style = Style::default().modifer(Modifier::BOLD);
let style = style.patch(Style::default().add_modifier(Modifier::ITALIC));
// style.modifer == Modifier::BOLD | Modifier::ITALIC, the modifier has been enriched not overidden

• Style::modifier has been removed in favor of Style::add_modifier and Style::remove_modifier.
• Buffer::set_style has been added. Buffer::set_background is deprecated.
• BarChart::style no longer set the style of the bars. Use BarChart::bar_style in replacement.
• Gauge::style no longer set the style of the gauge. Use Gauge::gauge_style in replacement.

List with item on multiple lines

The List widget has been refactored once again to support items with variable heights and complex
styling.

• List::new expects an input that can be converted to a Vec<ListItem> where ListItem is a
  wrapper around the item content to provide additional styling capabilities. ListItem contains a
  Text.
• List::items has been removed.

// Before
let items = vec![
  "Item1",
  "Item2",
  "Item3"
];
List::default().items(items.iters());

// After
let items = vec![
  ListItem::new("Item1"),
  ListItem::new("Item2"),
  ListItem::new("Item3"),
];
List::new(items);

See the examples for more advanced usages.

More wrapping options

Paragraph::wrap expects Wrap instead of bool to let users decided whether they want to trim
whitespaces when the text is wrapped.

// before
Paragraph::new(text).wrap(true)
// after
Paragraph::new(text).wrap(Wrap { trim: true }) // to have the same behavior
Paragraph::new(text).wrap(Wrap { trim: false }) // to use the new behavior

Horizontal scrolling in paragraph

You can now scroll horizontally in Paragraph. The argument of Paragraph::scroll has thus be
changed from u16 to (u16, u16).

Features

Serialization of style

You can now serialize and de-serialize Style using the optional serde feature.

Bug Fixes

• Fix out of bounds panic in widgets::Tabs when the widget is rendered on small areas.

Bug Fixes

• Ignore zero-width graphemes in Buffer::set_stringn.

Bug Fixes

• Fix usize overflows in widgets::Chart when a dataset is empty.

Bug Fixes

• Fix usize overflows in widgets::canvas::Line drawing algorithm.

Bug Fixes

• The List widget now takes into account the width of the highlight_symbol when calculating the total width of its items. It prevents items to overflow outside of the widget area.

Features

• Introduce stateful widgets, i.e widgets that can take advantage of keeping some state around between two draw calls (#210 goes a bit more into the details).
• Allow a Table row to be selected.

// State initialization
let mut state = TableState::default();

// In the terminal.draw closure
let header = ["Col1", "Col2", "Col"];
let rows = [
  Row::Data(["Row11", "Row12", "Row13"].into_iter())
];
let table = Table::new(header.into_iter(), rows.into_iter());
f.render_stateful_widget(table, area, &mut state);

// In response to some event:
state.select(Some(1));

• Add a way to choose the type of border used to draw a block. You can now choose from plain, rounded, double and thick lines.
• Add a graph_type property on the Dataset of a Chart widget. By default it will be Scatter where the points are drawn as is. An other option is Line where a line will be draw between each consecutive points of the dataset.
• Style methods are now const, allowing you to initialize const Style objects.
• Improve control over whether the legend in the Chart widget is shown or not. You can now set custom constraints using Chart::hidden_legend_constraints.
• Add Table::header_gap to add some space between the header and the first row.
• Remove log from the dependencies
• Add a way to use a restricted set of unicode symbols in several widgets to improve portability in exchange of a degraded output. (see BarChart::bar_set, Sparkline::bar_set and Canvas::marker). You can check how the --enhanced-graphics flag is used in the demos.

Breaking Changes

• Widget::render has been deleted. You should now use Frame::render_widget to render a widget on the corresponding Frame. This makes the Widget implementation totally decoupled from the Frame.

// Before
Block::default().render(&mut f, size);

// After
let block = Block::default();
f.render_widget(block, size);

• Widget::draw has been renamed to Widget::render and the signature has been updated to reflect that widgets are consumable objects. Thus the method takes self instead of &mut self.

// Before
impl Widget for MyWidget {
  fn draw(&mut self, area: Rect, buf: &mut Buffer) {
  }
}

/// After
impl Widget for MyWidget {
  fn render(self, arera: Rect, buf: &mut Buffer) {
  }
}

• Widget::background has been replaced by Buffer::set_background

// Before
impl Widget for MyWidget {
  fn render(self, arera: Rect, buf: &mut Buffer) {
    self.background(area, buf, self.style.bg);
  }
}

// After
impl Widget for MyWidget {
  fn render(self, arera: Rect, buf: &mut Buffer) {
    buf.set_background(area, self.style.bg);
  }
}

• Update the Shape trait for objects that can be draw on a Canvas widgets. Instead of returning an iterator over its points, a Shape is given a Painter object that provides a paint as well as a get_point method. This gives the Shape more information about the surface it will be drawn to. In particular, this change allows the Line shape to use a more precise and efficient drawing algorithm (Bresenham's line algorithm).
• SelectableList has been deleted. You can now take advantage of the associated ListState of the List widget to select an item.

// Before
List::new(&["Item1", "Item2", "Item3"])
  .select(Some(1))
  .render(&mut f, area);

// After

// State initialization
let mut state = ListState::default();

// In the terminal.draw closure
let list = List::new(&["Item1", "Item2", "Item3"]);
f.render_stateful_widget(list, area, &mut state);

// In response to some events
state.select(Some(1));

• widgets::Marker has been moved to symbols::Marker

Breaking Changes

• Bump crossterm to 0.14.
• Add cross symbol to the symbols list.

Bug Fixes

• Use the value of title_style to style the title of Axis.

Breaking Changes

• Use Constraint instead of integers to specify the widths of the Table widget's columns. This will allow more responsive tables.

Table::new(header, row)
  .widths(&[15, 15, 10])
  .render(f, chunk);

becomes:

Table::new(header, row)
  .widths(&[
    Constraint::Length(15),
    Constraint::Length(15),
    Constraint::Length(10),
  ])
  .render(f, chunk);

• Bump crossterm to 0.13.
• Use Github Actions for CI (Travis and Azure Pipelines integrations have been deleted).

Features

• Add support for horizontal and vertical margins in Layout.

Features

• Text implements PartialEq

Bug Fixes

• Avoid overflow errors in canvas

Bug Fixes

• Avoid a division by zero when all values in a barchart are equal to 0.
• Fix the inverted cursor position in the curses backend.
• Ensure that the correct terminal size is returned when using the crossterm backend.
• Avoid highlighting the separator after the selected item in the Tabs widget.

Breaking Changes

• Update crossterm backend

Bug Fixes

• Fix a panic in the Sparkline widget

Features

• Add a new curses backend (with Windows support thanks to pancurses).
• Add Backend::get_cursor and Backend::set_cursor methods to query and set the position of the cursor.
• Add more constructors to the Crossterm backend.
• Add a demo for all backends using a shared UI and application state.
• Add Ratio as a new variant of layout Constraint. It can be used to define exact ratios constraints.

Breaking Changes

• Add support for multiple modifiers on the same Style by changing Modifier from an enum to a bitflags struct.

So instead of writing:

let style = Style::default().add_modifier(Modifier::Italic);

one should use:

let style = Style::default().add_modifier(Modifier::ITALIC);
// or
let style = Style::default().add_modifier(Modifier::ITALIC | Modifier::BOLD);

Bug Fixes

• Ensure correct behavoir of the alternate screens with the Crossterm backend.
• Fix out of bounds panic when two Buffer are merged.

Features

• Add a new canvas shape: Rectangle.
• Official support of Crossterm backend.
• Make it possible to choose the divider between Tabs.
• Add word wrapping on Paragraph.
• The gauge widget accepts a ratio (f64 between 0 and 1) in addition of a percentage.

Breaking Changes

• Upgrade to Rust 2018 edition.

Bug Fixes

• Fix rendering of double-width characters.
• Fix race condition on the size of the terminal and expose a size that is safe to use when drawing through Frame::size.
• Prevent unsigned int overflow on large screens.

Features

• Add experimental test backend

Features

• show_cursor is called when Terminal is dropped if the cursor is hidden.

Breaking Changes

• Remove custom termion backends. This is motivated by the fact that termion structs are meant to be combined/wrapped to provide additional functionalities to the terminal (e.g AlternateScreen, Mouse support, ...). Thus providing exclusive types do not make a lot of sense and give a false hint that additional features cannot be used together. The recommended approach is now to create your own version of stdout:

let stdout = io::stdout().into_raw_mode()?;
let stdout = MouseTerminal::from(stdout);
let stdout = AlternateScreen::from(stdout);

and then to create the corresponding termion backend:

let backend = TermionBackend::new(stdout);

The resulting code is more verbose but it works with all combinations of additional termion features.

Breaking Changes

• Replace Item by a generic and flexible Text that can be used in both Paragraph and List widgets.
• Remove unecessary borrows on Style.

Features

• Add a basic Crossterm backend

Breaking Changes

• Remove Group and introduce Layout in its place
  • Terminal is no longer required to compute a layout
  • Size has been renamed Constraint
• Widgets are rendered on a Frame instead of a Terminal in order to avoid mixing draw and render calls
• draw on Terminal expects a closure where the UI is built by rendering widgets on the given Frame
• Update Widget trait
  • draw takes area by value
  • render takes a Frame instead of a Terminal
• All widgets use the consumable builder pattern
• SelectableList can have no selected item and the highlight symbol is hidden in this case
• Remove markup langage inside Paragraph. Paragraph now expects an iterator of Text items

Features

• Add start_corner option for List
• Add more text aligment options for Paragraph

Features

• Terminal implements Debug

Breaking Changes

• Use FnOnce instead of FnMut in Group::render

Features

• Add AlternateScreenBackend in termion backend
• Add TermionBackend::with_stdout in order to let an user of the library provides its own termion struct
• Add tests and documentation for Buffer::pos_of
• Remove leading whitespaces when wrapping text

Bug Fixes

• Fix debug_assert in Buffer::pos_of
• Pass the style of SelectableList to the underlying List
• Fix missing character when wrapping text
• Fix panic when specifying layout constraints

Features

• Add MouseBackend in termion backend to handle scroll and mouse events
• Add generic Item for items in a List
• Drop log4rs as a dev-dependencies in favor of stderrlog

Breaking Changes

• Rename TermionBackend to RawBackend (to distinguish it from the MouseBackend)
• Generic parameters for List to allow passing iterators as items
• Generic parameters for Table to allow using iterators as rows and header
• Generic parameters for Tabs
• Rename border bitflags to Borders